Mesoporous carbon materials

ABSTRACT

The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than −2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/468,946, filed May 20, 2009, the entire content and disclosure ofwhich are incorporated herein by reference.

This invention was made with government support under Contract NumberDE-AC05-00OR22725 between the United States Department of Energy andUT-Battelle, LLC. The U.S. government has certain rights in thisinvention.

FIELD OF THE INVENTION

The present invention relates to the field of porous carbon materials,and more particularly, to mesoporous carbon materials and films.

BACKGROUND OF THE INVENTION

Mesoporous carbon materials are three-dimensionally connected carbonframeworks containing pores within the size range of 2-50 nm (i.e.,mesopores). These materials have found an increasing number ofutilities, e.g., as gas separation, water purification (i.e.,nanofiltration), catalyst support, and electrode materials.

However, there are several problems currently being encountered in themanufacture of mesoporous carbon materials. One significant problem isthe difficulty (i.e., slowness) of organic precursors to react (i.e.,cure) in forming a polymer which functions as a carbon frameworkprecursor. Often, the polymer formation step is either incomplete, oralternatively, requires an excessive amount of time for curing to becompleted (e.g., days or weeks). In addition, the manufacture ofmesoporous carbon materials is generally conducted according to alaborious stepwise procedure, which is both time consuming and costly.

There are also several deficiencies commonly encountered in carbonmesoporous materials produced by these methods. For example, mesoporouscarbon materials are generally prone at elevated temperatures (i.e.,carbonization temperatures used in their manufacture) to structuralshrinkage. The structural shrinkage is often accompanied by a loss ofmesoporosity and an onset of microporosity. Mesoporous carbon materials,particularly films, are also prone to cracking.

Accordingly, there would be a particular benefit in a method capable ofproducing highly resilient mesoporous carbon materials. There would be afurther benefit if such a method was more efficient and less costly thanexisting methods. Moreover, the applicability of the resultingmesoporous carbon materials would advantageously be expanded to the manyprocesses that could benefit from exceptionally durable andheat-resistant mesoporous carbon materials.

SUMMARY OF THE INVENTION

In one aspect, the invention is directed to an improved method forfabricating a mesoporous carbon material. In another aspect, theinvention is directed to a mesoporous carbon material produced accordingto the method described above.

In a preferred embodiment, the method involves subjecting a precursorcomposition to a curing step followed by a carbonization step, theprecursor composition containing the following components: (i) atemplating component comprised of a block copolymer, (ii) a phenoliccompound or material, (iii) a crosslinkable aldehyde component, and (iv)at least 0.5 molar (i.e., 0.5 M) concentration of a strong acid having apKa of less than −2, wherein the carbonization conditions involveheating the precursor composition at a carbonizing temperature forsufficient time to convert the precursor composition to a mesoporouscarbon material.

By virtue of the strongly acidic conditions used (i.e., a strong acidpresent in a concentration of at least 0.5M), a more completelycrosslinked (i.e., cured) polymeric carbonization precursor is produced.The more completely crosslinked precursor results in a mesoporous carbonmaterial that is significantly less prone to shrinkage or cracking,particularly at elevated temperatures. Moreover, the strongly acidicconditions permit the resulting improved carbon material to be producedin significantly less time than methods of the art, even when applied tophenolic precursor compounds generally known to have a low reactivity(e.g., phenol, deactivated phenol derivatives, and polyphenol compoundsof high molecular weight, such as the tannins). The highly acidicconditions also permit the method to be conveniently practiced as aone-step process, i.e., wherein all components (e.g., templatingcomponents, carbon precursors, and acid) are mixed together andsubjected to curing and carbonization conditions, thereby dispensingwith the multi-step processes of the art.

The resulting mesoporous carbon material possesses several advantageousproperties, including an improved thermal stability as evidenced by asubstantial absence of structural shrinkage, and/or a substantialpreservation of mesoporosity, and/or a substantial preservation of BETsurface area of the mesoporous carbon material, after subjecting themesoporous carbon material to a heat-treatment temperature of at least1800° C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A,B. Nitrogen (N₂) sorption isotherm (FIG. 1A) and low-angle XRDpattern (FIG. 1B) of a resorcinol/formaldehyde/F-127 poloxamermesoporous carbon material of the invention (denoted as C-ORNL-1), alongwith pore size distribution plot in FIG. 1A.

FIGS. 2A-2C. High-resolution SEM image (FIG. 2A) and TEM images ofC-ORNL-1 along the [001] (FIG. 2B) and [110] (FIG. 2C) directions.

FIG. 3. Nitrogen sorption isotherm of a catechol/formaldehyde/F-127poloxamer mesoporous carbon material of the invention (denoted asC-ORNL-1-c), along with PSD insert.

FIG. 4. Low-angle XRD pattern of C-ORNL-1-c.

FIGS. 5A,B. High-resolution SEM image (FIG. 5A) and TEM image (FIG. 5B)of C-ORNL-1-c.

FIGS. 6A-6D. Low-angle (FIG. 6A) and wide-angle (FIG. 6B) XRD patterns,nitrogen sorption isotherms (FIG. 6C), and pore size distribution plots(FIG. 6D) of C-ORNL-1 after heat-treatment at different temperatures.For clarity, the nitrogen sorption isotherm of C-ORNL-1-1800 was shiftedup by 50 cm³ STP/g.

FIGS. 7A-7F. High-resolution SEM images (FIGS. 7A, C, E, F) and TEMimages (FIGS. 7B, D) of C-ORNL-1 after heat treatment at differenttemperatures.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, the invention is directed to a method for fabricating amesoporous carbon material. As used herein and as understood in the art,the term “mesoporous” indicates a material containing “mesopores”, whichare pores having a diameter (i.e., pore size) of between 2 and 50 nm. Incontrast to mesopores, micropores (and thus, microporous materials) aregenerally understood to have pore diameters of less than 2 nm, whereasmacropores (and thus, macroporous materials) are generally understood tohave pore diameters greater than 50 nm.

The method first involves providing (i.e., preparing or otherwiseobtaining in prepared form) a precursor composition which will besubjected to a curing step followed by a carbonization step in order toproduce a mesoporous carbon material of the invention. The precursorcomposition includes at least the following components: (i) a templatingcomponent containing a block copolymer, (ii) a phenolic compound ormaterial, (iii) a crosslinkable aldehyde component, and (iv) at least0.5 M concentration of a strong acid having a pKa of less than −2. Thecombination of phenolic compound/material and the crosslinkable aldehydeare herein referred to as the “polymer precursor” or “polymer precursorcomponents”. The resulting polymer (i.e., after polymerization andcrosslinking) functions as the carbonization precursor, i.e., the sourceof carbon upon being carbonized. In contrast, the templating component(i.e., block copolymer) functions to organize the polymer precursormaterials in an ordered (i.e., patterned) arrangement before thecarbonization step. During carbonization, the block copolymer istypically completely volatized into gaseous byproducts, and thereby,generally does not contribute to formation of solid carbon. However, thevolatile gases serve the important role of creating the mesopores in thecarbon structure during the carbonization step.

The templating component can contain one or more block copolymers. Asused herein, a “block copolymer” is a polymer containing two or morechemically distinguished polymeric blocks (i.e., sections or segments).The copolymer can be, for example, a diblock copolymer (e.g., A-B),triblock copolymer (e.g., A-B-C), tetrablock copolymer (e.g., A-B-C-D),or higher block copolymer, wherein A, B, C, and D represent chemicallydistinct polymeric segments. The block copolymer is preferably notcompletely inorganic, and more preferably, completely organic (i.e.,carbon-based) in order that the block copolymer is at least partiallycapable of volatilizing during the carbonization step. Preferably, theblock copolymer contains at least two segments that possess a differencein hydrophilicity or hydrophobicity (i.e., is amphiphilic). Such blockcopolymers typically form periodic structures by virtue of selectiveinteractions between like domains, i.e., between hydrophobic domains andbetween hydrophilic domains. The block copolymer is typically linear;however, branched (e.g., glycerol branching units) and grafted blockcopolymer variations are also contemplated herein. Preferably, the blockcopolymer contains polar groups capable of interacting (e.g., byhydrogen or ionic bonding) with the phenolic compound or material. Forthis reason, the block copolymer is preferably not a completehydrocarbon such as styrene-butadiene. Some of the groups preferablylocated in the block copolymer which can provide a favorable interactivebond with phenol groups include, for example, hydroxy, amino, imino, andcarbonyl groups.

Some general examples of suitable classes of block copolymers includethose containing segments of polyacrylate or polymethacrylate (andesters thereof), polystyrene, polyethyleneoxide, polypropyleneoxide,polyethylene, polyacrylonitrile, polylactide, and polycaprolactone. Somespecific examples of suitable block copolymers includepolystyrene-b-poly(methylmethacrylate) (i.e., PS-PMMA),polystyrene-b-poly(acrylic acid) (i.e., PS-PAA),polystyrene-b-poly(4-vinylpyridine) (i.e., PS-P4VP),polystyrene-b-poly(2-vinylpyridine) (i.e., PS-P2VP),polyethylene-b-poly(4-vinylpyridine) (i.e., PE-P4VP),polystyrene-b-polyethyleneoxide (i.e., PS-PEO),polystyrene-b-poly(4-hydroxystyrene),polyethyleneoxide-b-polypropyleneoxide (i.e., PEO-PPO),polyethyleneoxide-b-poly(4-vinylpyridine) (i.e., PEO-P4VP),polyethylene-b-polyethyleneoxide (i.e., PE-PEO),polystyrene-b-poly(D,L-lactide),polystyrene-b-poly(methylmethacrylate)-b-polyethyleneoxide (i.e.,PS-PMMA-PEO), polystyrene-b-polyacrylamide,polystyrene-b-polydimethylacrylamide (i.e., PS-PDMA),polystyrene-b-polyacrylonitrile (i.e., PS-PAN), andpolyethyleneoxide-b-polyacrylonitrile (i.e., PEO-PAN).

In a preferred embodiment, the block copolymer is a triblock copolymercontaining one or more poly-EO segments and one or more poly-PPOsegments. More preferably, the triblock copolymer is a poloxamer (i.e.Pluronic® or Lutrol® polymer) according to the general formula

(PEO)_(a)—(PPO)_(b)—(PEO)_(c)  (1)

wherein PEO is a polyethylene oxide block and PPO is a polypropyleneblock (i.e., —CH₂CH(CH₃)O— or —CH(CH₃)CH₂O—), and the subscripts a, b,and c represent the number of monomer units of PEO and PPO, asindicated. Typically, a, b, and c are each at least 2, and moretypically, at least 5, and typically up to a value of 100, 120, or 130.Subscripts a and c are typically of equal value in these types ofpolymers. In different embodiments, a, b, and c can independently have avalue of about, or at least, or up to 10, 20, 30, 40, 50, 60, 70, 80,90, 100, 120, 130, 140, 150, 160, 180, 200, 220, 240, or any particularrange established by any two of these exemplary values.

In one embodiment, a and c values are each less than b, i.e., thehydrophilic PEO block is shorter on each end than the hydrophobic PPOblock. For example, in different embodiments, a, b, and c can eachindependently have a value of 2, 5, 7, 10, 12, 15, 20, 25, 30, 35, 40,45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140,150, or 160, or any range delimited by any two of these values, providedthat a and c values are each less than b. Furthermore, in differentembodiments, it can be preferred for the a and c values to be less thanb by a certain number of units, e.g., by 2, 5, 7, 10, 12, 15, 20, 25,30, 35, 40, 45, or 50 units, or any range therein. Alternatively, it canbe preferred for the a and c values to be a certain fraction orpercentage of b (or less than or greater than this fraction orpercentage), e.g., about 10%, 20%, 25%, 30, 33%, 40%, 50%, 60%, 70%,75%, 80%, 85%, 90%, or any range delimited by any two of these values.

In another embodiment, a and c values are each greater than b, i.e., thehydrophilic PEO block is longer on each end than the hydrophobic PPOblock. For example, in different embodiments, a, b, and c can eachindependently have a value of 2, 5, 7, 10, 12, 15, 20, 25, 30, 35, 40,45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140,150, or 160, or any range delimited by any two of these values, providedthat a and c values are each greater than b. Furthermore, in differentembodiments, it can be preferred for the a and c values to be greaterthan b by a certain number of units, e.g., by 2, 5, 7, 10, 12, 15, 20,25, 30, 35, 40, 45, or 50 units, or any range therein. Alternatively, itcan be preferred for the b value to be a certain fraction or percentageof a and c values (or less than or greater than this fraction orpercentage), e.g., about 10%, 20%, 25%, 30, 33%, 40%, 50%, 60%, 70%,75%, 80%, 85%, 90%, or any range delimited by any two of these values.

In different embodiments, the poloxamer preferably has a minimum averagemolecular weight of at least 500, 800, 1000, 1200, 1500, 2000, 2500,3000, 3500, 4000, or 4500 g/mole, and a maximum average molecular weightof 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10,000,12,000, 15,000, or 20,000 g/mole, wherein a particular range can beestablished between any two of the foregoing values, and particularly,between any two the minimum and maximum values. The viscosity of thepolymers is generally at least 200, 250, 300, 350, 400, 450, 500, 550,600, or 650 centipoise (cps), and generally up to 700, 800, 900, 1000,1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000,or 7500 cps, or any particular range established between any two of theforegoing values.

The following table lists several exemplary poloxamer polymersapplicable to the present invention.

TABLE 1 Some exemplary poloxamer polymers Approxi- Pluronic ®Approximate Approximate mate Generic Name Name value of a value of bvalue of c Poloxamer 101 Pluronic L-31 2 16 2 Poloxamer 105 PluronicL-35 11 16 11 Poloxamer 108 Pluronic F-38 46 16 46 Poloxamer 122 — 5 215 Poloxamer 123 Pluronic L-43 7 21 7 Poloxamer 124 Pluronic L-44 11 2111 Poloxamer 181 Pluronic L-61 3 30 3 Poloxamer 182 Pluronic L-62 8 30 8Poloxamer 183 — 10 30 10 Poloxamer 184 Pluronic L-64 13 30 13 Poloxamer185 Pluronic P-65 19 30 19 Poloxamer 188 Pluronic F-68 75 30 75Poloxamer 212 — 8 35 8 Poloxamer 215 — 24 35 24 Poloxamer 217 PluronicF-77 52 35 52 Poloxamer 231 Pluronic L-81 6 39 6 Poloxamer 234 PluronicP-84 22 39 22 Poloxamer 235 Pluronic P-85 27 39 27 Poloxamer 237Pluronic F-87 62 39 62 Poloxamer 238 Pluronic F-88 97 39 97 Poloxamer282 Pluronic L-92 10 47 10 Poloxamer 284 — 21 47 21 Poloxamer 288Pluronic F-98 122 47 122 Poloxamer 331 Pluronic L-101 7 54 7 Poloxamer333 Pluronic P-103 20 54 20 Poloxamer 334 Pluronic P-104 31 54 31Poloxamer 335 Pluronic P-105 38 54 38 Poloxamer 338 Pluronic F-108 12854 128 Poloxamer 401 Pluronic L-121 6 67 6 Poloxamer 403 Pluronic P-12321 67 21 Poloxamer 407 Pluronic F-127 98 67 98

As known in the art, the names of the poloxamers and Pluronics (as givenabove) contain numbers which provide information on the chemicalcomposition. For example, the generic poloxamer name contains threedigits, wherein the first two digits×100 indicates the approximatemolecular weight of the PPO portion and the last digit×10 indicates theweight percent of the PEO portion. Accordingly, poloxamer 338 possessesa PPO portion of about 3300 g/mole molecular weight, and 80 wt % PEO. Inthe Pluronic name, the letter indicates the physical form of theproduct, i.e., L=liquid, P=paste, and F=solid, i.e., flake. The firstdigit, or two digits for a three-digit number, multiplied by 300,indicates the approximate molecular weight of the PPO portion, while thelast digit×10 indicates the weight percent of the PEO portion. Forexample, Pluronic® F-108 (which corresponds to poloxamer 338) indicatesa solid form composed of about 3,000 g/mol of the PPO portion and 80 wt% PEO.

Numerous other types of copolymers containing PEO and PPO blocks arepossible, all of which are applicable herein. For example, the blockcopolymer can also be a reverse poloxamer of general formula:

(PPO)_(a)—(PEO)_(b)—(PPO)_(c)  (2)

wherein all of the details considered above with respect to the regularpoloxamers (e.g., description of a, b, and c subscripts, and all of theother exemplary structural possibilities) are applicable by referenceherein to the reverse poloxamers.

In another variation, the block copolymer contains a linking diaminegroup (e.g., ethylenediamine, i.e., EDA) or triamine group (e.g.,melamine). Some examples of such copolymers include the Tetronics®(e.g., PEO-PPO-EDA-PPO-PEO) and reverse Tetronics® (e.g.,PPO-PEO-EDA-PEO-PPO).

The phenolic compound or material of the precursor composition can beany phenolic compound or material that can react by a condensationreaction with an aldehydic compound or material (e.g., formaldehyde)under acidic conditions. Typically, any compound or material containinga hydroxy group bound to an aromatic ring (typically, a phenyl ring) issuitable for the present invention as a phenolic compound or material.

In one embodiment, the phenolic compound or material contains one phenolgroup (i.e., one hydroxy group bound to a six-membered aromatic ring).Some examples of such compounds include phenol, the halophenols, theaminophenols, the hydrocarbyl-substituted phenols (wherein “hydrocarbyl”includes, e.g., straight-chained, branched, or cyclic alkyl, alkenyl, oralkynyl groups typically containing from 1 to 6 carbon atoms, optionallysubstituted with one or more oxygen or nitrogen atoms), naphthols,nitrophenols, hydroxyanisoles, hydroxybenzoic acids, fatty acidester-substituted or polyalkyleneoxy-substituted phenols (e.g., on the 2or 4 positions with respect to the hydroxy group), phenols containing anazo linkage (e.g., p-hydroxyazobenzene), and phenolsulfonic acids (e.g.,p-phenolsulfonic acid). Some general subclasses of halophenols includethe fluorophenols, chlorophenols, bromophenols, and iodophenols, andtheir further sub-classification as, for example, p-halophenols (e.g.,4-fluorophenol, 4-chlorophenol, 4-bromophenol, and 4-iodophenol),m-halophenols (e.g., 3-fluorophenol, 3-chlorophenol, 3-bromophenol, and3-iodophenol), o-halophenols (e.g., 2-fluorophenol, 2-chlorophenol,2-bromophenol, and 2-iodophenol), dihalophenols (e.g.,3,5-dichlorophenol and 3,5-dibromophenol), and trihalophenols (e.g.,3,4,5-trichlorophenol, 3,4,5-tribromophenol, 3,4,5-trifluorophenol,3,5,6-trichlorophenol, and 2,3,5-tribromophenol). Some examples ofaminophenols include 2-, 3-, and 4-aminophenol, and 3,5- and2,5-diaminophenol. Some examples of nitrophenols include 2-, 3-, and4-nitrophenol, and 2,5- and 3,5-dinitrophenol. Some examples ofhydrocarbyl-substituted phenols include the cresols, i.e., methylphenolsor hydroxytoluenes (e.g., o-cresol, m-cresol, p-cresol), the xylenols(e.g., 3,5-, 2,5-, 2,3-, and 3,4-dimethylphenol), the ethylphenols(e.g., 2-, 3-, and 4-ethylphenol, and 3,5- and 2,5-diethylphenol),n-propylphenols (e.g., 4-n-propylphenol), isopropylphenols (e.g.,4-isopropylphenol), butylphenols (e.g., 4-n-butylphenol,4-isobutylphenol, 4-t-butylphenol, 3,5-di-t-butylphenol,2,5-di-t-butylphenol), hexylphenols, octyl phenols (e.g.,4-n-octylphenol), nonylphenols (e.g., 4-n-nonylphenol), phenylphenols(e.g., 2-phenylphenol, 3-phenylphenol, and 4-phenylphenol), andhydroxycinnamic acid (p-coumaric acid). Some examples of hydroxyanisolesinclude 2-methoxyphenol, 3-methoxyphenol, 4-methoxyphenol,3-t-butyl-4-hydroxyanisole (e.g., BHA), and ferulic acid. Some examplesof hydroxybenzoic acids include 2-hydroxybenzoic acid (salicylic acid),3-hydroxybenzoic acid, 4-hydroxybenzoic acid, and their organic acidesters (e.g., methyl salicylate and ethyl-4-hydroxybenzoate).

In another embodiment, the phenolic compound or material contains twophenol groups. Some examples of such compounds include catechol,resorcinol, hydroquinone, the hydrocarbyl-linked bis-phenols (e.g.,bis-phenol A, methylenebisphenol, and 4,4′-dihydroxystilbene),4,4′-biphenol, the halo-substituted diphenols (e.g., 2-haloresorcinols,3-haloresorcinols, and 4-haloresorcinols, wherein the halo group can befluoro, chloro, bromo, or iodo), the amino-substituted diphenols (e.g.,2-aminoresorcinol, 3-aminoresorcinol, and 4-aminoresorcinol), thehydrocarbyl-substituted diphenols (e.g., 2,6-dihydroxytoluene, i.e.,2-methylresorcinol; 2,3-, 2,4-, 2,5-, and 3,5-dihydroxytoluene,1-ethyl-2,6-dihydroxybenzene, caffeic acid, and chlorogenic acid), thenitro-substituted diphenols (e.g., 2- and 4-nitroresorcinol),dihydroxyanisoles (e.g., 3,5-, 2,3-, 2,5-, and 2,6-dihydroxyanisole, andvanillin), dihydroxybenzoic acids (e.g., 3,5-, 2,3-, 2,5-, and2,6-dihydroxybenzoic acid, and their alkyl esters, and vanillic acid),and phenolphthalein.

In another embodiment, the phenolic compound or material contains threephenol groups. Some examples of such compounds include phloroglucinol(1,3,5-trihydroxybenzene), pyrogallol (1,2,3-trihydroxybenzene),1,2,4-trihydroxybenzene, 5-chloro-1,2,4-trihydroxybenzene, resveratrol(trans-3,5,4′-trihydroxystilbene), the hydrocarbyl-substitutedtriphenols (e.g., 2,4,6-trihydroxytoluene, i.e., methylphloroglucinol,and 3,4,5-trihydroxytoluene), the halogen-substituted triphenols (e.g.,5-chloro-1,2,4-trihydroxybenzene), the carboxy-substituted triphenols(e.g., 3,4,5-trihydroxybenzoic acid, i.e., gallic acid or quinic acid,and 2,4,6-trihydroxybenzoic acid), the nitro-substituted triphenols(e.g., 2,4,6-trihydroxynitrobenzene), and phenol-formaldehyde resoles ornovolak resins containing three phenol groups.

In yet another embodiment, the phenolic compound or material containsmultiple (i.e., greater than three) phenol groups. Some examples of suchcompounds or materials include tannin (e.g., tannic acid), tanninderivatives (e.g., ellagotannins and gallotannins), phenol-containingpolymers (e.g., poly-(4-hydroxystyrene)), phenol-formaldehyde resoles ornovolak resins containing at least four phenol groups (e.g., at least 4,5, or 6 phenol groups), quercetin, ellagic acid, and tetraphenol ethane.

The crosslinkable aldehyde component can be any organic compound ormaterial containing an aldehyde group. Typically, the crosslinkablealdehyde is formaldehyde. However, there are also numerousorganoaldehydes, organodialdehydes, and polyaldehydes (e.g.,organotrialdehydes, organotetraaldehydes, and so on) considered hereinwhich can serve the same purpose. The organoaldehydes can be generallyrepresented by the following formula:

R—CHO  (3)

wherein R can represent a straight-chained, branched, or cyclic, andeither saturated or unsaturated hydrocarbyl group, typically containingat least 1, 2, or 3 carbon atoms, and up to 4, 5, 6, 7, or 8 carbonatoms. Some examples of suitable organoaldehydes include acetaldehyde,propanal (propionaldehyde), butanal (butyraldehyde), pentanal(valeraldehyde), hexanal, crotonaldehyde, acrolein, benzaldehyde, andfurfural.

The organodialdehydes can be generally represented by the followingformula:

OHC—R—CHO  (4)

wherein R is a straight-chained, branched, or cyclic, and eithersaturated or unsaturated, hydrocarbyl linking group, typicallycontaining at least 1, 2, or 3 carbon atoms, and up to 4, 5, 6, 7, 8, 9,or 10 carbon atoms. Some examples of dialdehyde compounds includeglyoxal, malondialdehyde, succinaldehyde, glutaraldehyde, adipaldehyde,pimelaldehyde, suberaldehyde, sebacaldehyde, cyclopentanedialdehyde,terephthaldehyde, and furfuraldehyde.

The strong acid component contains one or more acids having a pKa of orless than about −2. Some examples of such acids include hydrochloricacid, hydrobromic acid, hydroiodic acid, sulfuric acid, and thesuperacids, such as triflic acid. In the method, a molar concentrationof at least 0.5 molar (i.e., 0.5 M) with respect to the total volume ofprecursor composition is preferred. In particular embodiments, the molarconcentration of the acid can preferably be about or at least 0.5 M, 0.6M, 0.7 M, 0.8 M, 1.0 M, 1.2 M, 1.5 M, 1.8 M, 2.0 M, or any rangeestablished between any two of the foregoing values. The molarconcentration values given may also be referred to in terms of molarequivalents of H⁺, or pH, wherein the pH for a strong acid generallyabides by the formula pH=−log [H⁺], wherein [H⁺] represents theconcentration of H⁺ ions.

Any one or more of the above components may also be dissolved in asuitable solvent. Preferably, the solvent is an organic polar protic ornon-protic solvent. Some examples of organic polar protic solventsinclude alcohols, e.g., methanol, ethanol, n-propanol, isopropanol,ethylene glycol, and the like. Some examples of organic polar non-proticsolvents include acetonitrile, dimethylformamide, dimethylsulfoxide,methylene chloride, organoethers (e.g., tetrahydrofuran ordiethylether), and the like.

In a particular embodiment, an orthoacetate, e.g., triethylorthoacetate, is excluded from the precursor composition. In anotherparticular embodiment, a weak acid (i.e., having a pKa above −2), andparticularly, the weak organic acids (e.g., p-toluenesulfonic acid orhypophosphorous acid), are excluded from the precursor composition. Inyet another particular embodiment, a phenol-formaldehyde resole ornovolak resin (e.g., those of 500-5000M.W.) is excluded from theprecursor composition.

In one embodiment, a multi-step process is employed by including one ormore steps before the curing and/or carbonization steps. For example, amulti-step process may be employed wherein a film of the templatingcomponent in combination with the phenolic compound or material is firstproduced by, for example, applying (i.e., coating) said components ontoa surface, and casting the components as a solid film by removingsolvent therefrom (e.g., by annealing). The produced film may then bereacted with the crosslinkable aldehyde component (e.g., by a vaporphase reaction with, for example, formaldehyde vapor) under strong acidconditions to produce the polymerized (and optionally, crosslinked)carbon precursor material. The resulting cured film can then becarbonized to produce the mesoporous carbon material.

However, the highly acidic condition employed in the current invention(i.e., use of a strong acid of or less than a pKa less than −2 and at aconcentration of at least 0.5 M) advantageously permits a one-step(i.e., “one-pot”) preparative method. In the one-step method, allcomponents, as described above, are combined directly before the curingand carbonization steps.

The curing step includes any of the conditions, as known in the art,which promote polymerization, and preferably, crosslinking, of polymerprecursors, and in particular, crosslinking between phenolic andaldehydic components. The curing conditions generally includeapplication of an elevated temperature for a specified period of time.However, other curing conditions and methods are contemplated herein,including radiative (e.g., UV curing) or purely chemical (i.e., withoutuse of an elevated temperature). Preferably, the curing step involvessubjecting the polymer precursors or the entire precursor composition toa temperature of at least 60, 70, 80, 90, 100, 110, 120, 130, or 140° C.for a time period of, typically, at least 0.5, 1, 2, 5, 10, or 12 hoursand up to 15, 20, 24, 36, 48, or 72 hours, wherein it is understood thathigher temperatures generally require shorter time periods.

In particular embodiments, it may be preferred to subject the precursorsto an initial lower temperature curing step followed by a highertemperature curing step. The initial curing step may employ atemperature of about, for example, 60, 70, 80, 90, or 100° C. (or arange between any of these), while the subsequent curing step may employa temperature of about, for example, 90, 100, 110, 120, 130, or 140° C.(or a range between any of these), provided that the temperature of theinitial curing step is less than the temperature of the subsequentcuring step. In addition, each curing step can employ any of theexemplary time periods given above.

Alternatively, it may be preferred to gradually increase the temperatureduring the curing step between any of the temperatures given above, orbetween room temperature (e.g., 15, 20, 25, 30, or 35° C.) and any ofthe temperatures given above. In different embodiments, the gradualincrease in temperature can be practiced by employing a temperatureincrease rate of, or at least, or no more than 1° C./min, 2° C./min, 3°C./min, 5° C./min, 7° C./min, 10° C./min, 12° C./min, 15° C./min, 20°C./min, or 30° C./min, or any suitable range between any of thesevalues. The gradual temperature increase can also include one or moreperiods of residency at a particular temperature, and/or a change in therate of temperature increase.

The carbonization step includes any of the conditions, as known in theart, which cause carbonization of the precursor composition. Generally,in different embodiments, a carbonization temperature of about or atleast 300° C., 350° C., 400° C., 450° C., 500° C., 550° C., 600° C.,650° C., 700° C., 750° C., 800° C., 850° C., 900° C., 950° C., 1000° C.,1050° C., 1100° C., 1150° C., 1200° C., 1250° C., 1300° C., 1350° C.,1400° C., 1450° C., 1500° C., 1600° C., 1700° C., or 1800° C. isemployed for a time period of, typically, at least 1, 2, 3, 4, 5, or 6hours and up to 7, 8, 9, 10, 11, or 12 hours, wherein it is understoodthat higher temperatures generally require shorter time periods toachieve the same result. If desired, the precursor composition, oralternatively, the carbonized material, can be subjected to atemperature high enough to produce a graphitized carbon material.Typically, the temperature capable of causing graphitization is atemperature of or greater than about 2000° C., 2100° C., 2200° C., 2300°C., 2400° C., 2500° C., 2600° C., 2700° C., 2800° C., 2900° C., 3000°C., 3100° C., or 3200° C., or a range between any two of thesetemperatures. Preferably, the carbonization or graphitization step isconducted in an atmosphere substantially removed of oxygen, e.g.,typically under an inert atmosphere. Some examples of inert atmospheresinclude nitrogen and the noble gases (e.g., helium or argon).

In particular embodiments, it may be preferred to subject the precursorsto an initial lower temperature carbonization step followed by a highertemperature carbonization step. The initial carbonization step mayemploy a temperature of about, for example, 300, 350, 400, 450, 500,550, 600, 650, 700, 750, 800, 850, or 900° C. (or a range between any ofthese), while the subsequent carbonization step may employ a temperatureof about, for example, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950,1000, 1050, 1100, 1200, 1250, 1300, 1400, 1450, 1500, 1600, 1700, or1800° C. (or a range between any of these), provided that thetemperature of the initial carbonization step is less than thetemperature of the subsequent carbonization step. In addition, eachcarbonization step can employ any of the exemplary time periods givenabove.

Alternatively, it may be preferred to gradually increase the temperatureduring the carbonization step between any of the temperatures givenabove, or between room temperature (e.g., 15, 20, 25, 30, or 35° C.) andany of the temperatures given above. In different embodiments, thegradual increase in temperature can be practiced by employing atemperature increase rate of, or at least, or no more than 1° C./min, 2°C./min, 3° C./min, 5° C./min, 7° C./min, 10° C./min, 12° C./min, 15°C./min, 20° C./min, 30° C./min, 40° C./min, or 50° C./min, or anysuitable range between any of these values. The gradual temperatureincrease can also include one or more periods of residency at aparticular temperature, and/or a change in the rate of temperatureincrease.

In a preferred embodiment, after combining the components of theprecursor composition, and before curing or carbonization, the solutionis stirred for a sufficient period of time (e.g., at least or about 1,2, 5, 10, 20, 30, 40, 50, 60, 90, or 120 minutes, or a range between anythese values) until the solution turns turbid. The turbidity indicatesformation of an ordered nanocomposite gel or solid which has undergone adegree of phase separation from the liquid portion of the solution. Ifdesired, stirring can be continued after the onset of turbidity, suchthat the total amount of stirring time before curing, carbonization, ora phase-separation process is any of the exemplary time periods givenabove, or a much longer period of time, such as several hours (e.g., atleast or about 4, 5, 6, 7, 8, 10, or 12 hours) or days (e.g., at leastor about 1, 2, 3, 4, 5, 10, 15, or 20 days), or a range between of theforegoing exemplary periods of time.

More preferably, after turbidity becomes evident, the phase-separatedmixture is subjected to conditions that cause the ordered nanocompositegel or solid to be isolated from the liquid portion (i.e., phaseseparation conditions). Any separation method can be applied herein. Ina preferred embodiment, the phases are separated by centrifugation. Indifferent embodiments, the centrifugation can be conducted at an angularspeed of or at least, for example, 2000 rpm, 2500 rpm, 3000 rpm, 4000rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 9500 rpm, 10000rpm, 11000 rpm, 12000 rpm, or 15000 rpm, or a range between any of thesevalues, for a period of time of, for example, 0.1, 0.2, 0.5, 1, 2, 3, 4,5, or 6 minutes, wherein it is understood that higher angular speedsgenerally require less amounts of time to effect an equivalent degree ofseparation. Superspeed centrifugation (e.g., up to 20,000 or 30,000 rpm)or ultracentrifugation (e.g., up to 40,000, 50,000, 60,000, or 70,000rpm) can also be used. The gel or solid phase, once separated from theliquid phase, is preferably cured and carbonized in the substantialabsence of the liquid phase according to any of the conditions describedabove for these processes.

In a particular embodiment, the produced mesoporous carbon material isin the form of a film. The film can have any suitable thickness. Indifferent embodiments, the film may preferably have a thickness of, orat least, or less than 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm,600 nm, 700 nm, 800 nm, 900 nm, 1.0 μm, 1.2 μm, 1.5 μm, 2.0 μm, 2.5 μm,3.0 μm, 4.0 μm, 5.0 μm, 10 μm, 20 μm, 30 μm, 40 μm, or 50 μm, or a rangebetween any of these values. The film may also desirably function aspart of a composite material, wherein the carbon film either overlays,underlies, or is sandwiched between one or more layers of othermaterial. The other material may be porous or non-porous, and can becomposed of, for example, silica, alumina, graphite, a metal oxide, ororganic, inorganic, or hybrid polymer.

In another embodiment, the produced mesoporous carbon material is in theform of particles. The particles can be produced by any suitable method,such as, for example, the spray atomization techniques known in the artwhich also include a capability of heating at carbonizationtemperatures. For example, the precursor composition described above(typically, in a carrier solvent, such as THF or DMF) can be sprayedthrough the nozzle of an atomizer, and the particulates directed intoone or more heated chambers for curing and carbonization steps.Alternatively, a portion of the precursor composition (e.g., templatingagent and one of the polymer precursors, such as the phenolic) may firstbe atomized and the resulting particles annealed (i.e., dried) bysuitable conditions; the resulting particles then exposed to the otherpolymer precursor (e.g., formaldehyde) and subjected to strong acidconditions (as described above), followed by curing and carbonizationconditions. In different embodiments, the particles are at least orabout, for example, 50 nm, 100 nm, 200 nm, 500 nm, 1 μm, 2 μm, 5 μm, 10μm, 50 μm, 100 μm, 500 μm, or 1000 μm, or a range between any two ofthese values.

The mesoporous carbon material can also be functionalized, as desired,by methods known in the art for functionalizing carbon or graphitematerials. For example, the carbon material may be nitrogenated,fluorinated, or oxygenated by methods known in the art. The carbonmaterial may be nitrogenated, fluorinated, or oxygenated, by, forexample, exposure of the carbon film, either during or after thecarbonization process, to, respectively, ammonia, fluorine gas, oroxygen under suitably reactive conditions. In the particular case offluorination, the carbon material is typically placed in contact withfluorine gas for a period of several minutes (e.g., 10 minutes) up toseveral days at a temperature within 20° C. to 500° C., wherein the timeand temperature, among other factors, are selected based on the degreeof fluorination desired. For example, a reaction time of about 5 hoursat ambient temperature (e.g., 15-30° C.) typically results influorination of about 10% of the total carbon; in comparison,fluorination conducted at about 500° C. for two days results in about100% fluorination of the total carbon. In particular embodiments, thedegree of nitrogenation, fluorination, or oxygenation can be about or atleast 1%, 2%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or100%, or a range between any two of these values.

The produced mesoporous carbon material contains mesopores, i.e., poreshaving a diameter (i.e., pore size) of 2 to 50 nm. Preferably, thecarbon material possesses the mesopores in the substantial absence ofmicropores (pores of less than 2 nm) or macropores (pores of more than50 nm). By a “substantial absence” of micropores or macropores is meantthat no more than 5%, and more preferably, no more than about 1%, 0.5%,or 0.1% of the total pore volume is due to the presence of micropores ormacropores. In different embodiments, the carbon material preferablypossesses mesopores having a size (diameter) of about 2, 3, 4, 5, 6, 7,8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, or 50 nm, or a range betweenany two of these values. The pores of the carbon material can alsopossess a level of size uniformity, i.e., in pore diameters and/or poreshape. For example, in different embodiments, the pores of the carbonmaterial may possess an average pore diameter corresponding to any ofthe diameters exemplified above, subject to a degree of variation of nomore than, for example, ±10 nm, ±8 nm, ±6, nm, ±5 nm, ±4 nm, ±3 nm, ±2nm, or ±1 nm. The wall thickness of the mesopores is typically withinthe range of about 5.0-7.0 nm, e.g., 5.0, 5.5, 6.0, 6.5, or 7.0 nm, or arange between any two of these values.

Preferably, the mesopores are arranged relative to each other with acertain degree of order (i.e., in a patterned or ordered arrangement).Some examples of ordered arrangements include a hexagonal or cubicarrangement.

In addition, the longitudinal dimension of the mesopores can have aparticular orientation with respect to the surface, particularly for thecase of a film. For example, in one embodiment, it is preferred for thelongitudinal dimension of the mesopores to be oriented either completelyperpendicular to the surface (i.e., precisely 90°), or substantiallyperpendicular to the surface, e.g., 90±10° (i.e., 80° to)-80°, 90±5°,90±2°, or 90±1° with respect to the surface. An orientation of mesoporessubstantially perpendicular to the surface is particular advantageousfor the case when the carbon material (typically, a film or membrane) isapplied as a gas-permeable material. In another embodiment, it may bepreferred for a substantial portion of pores to have a longitudinaldimension oriented obliquely to the surface within a range of angles of,e.g., 45° to −45°, 60° to −60°, 70° to −70°, or 80° to −80°, withrespect to the surface. In yet another embodiment, it is preferred forthe longitudinal dimension of the mesopores to be oriented eithercompletely aligned (i.e., parallel) with the surface (i.e., precisely0°), or substantially aligned to the surface, e.g., 0±10°, 0±5°, 0±2°,or 0±1° with respect to the surface. A selected orientation of pores canbe accomplished by, for example, carbonizing a block of precursormaterial and then slicing or etching a selected surface having a desiredangle with respect to the longitudinal dimensions of the pores. Aselected orientation of pores may also be accomplished by, for example,adjusting the angle of the carbon material and/or by compression by anoverlayer during the carbonization step.

The mesoporous carbon material typically possesses a BET surface area ofabout or at least 50, 100, 200, 300, 400, 450, 500, 550, 600, 650, 700,750, or 800 m²/g, or a range between any two of these values. Themesoporous carbon material typically possesses a pore volume of about orat least 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, or 0.7cm³/g, or a range between any two of these values.

The mesoporous carbon material produced according to the methoddescribed above preferably possesses an improved physical resilience,such as an improved thermal stability and resistance to cracking. Animproved thermal stability is preferably evidenced by a substantialabsence of structural shrinkage, and/or a substantial preservation ofmesoporosity, and/or a substantial preservation of the BET surface areaafter being heat-treated at a temperature of at least 1800° C. In morepreferred embodiments, the improved thermal stability is evidenced afterheat treating the mesoporous carbon material at a temperature of atleast 1850° C., 1900° C., 1950° C., 2000° C., 2050° C., 2100° C., 2150°C., 2200° C., 2250° C., 2300° C., 2350° C., 2400° C., 2450° C., 2500°C., 2550° C., 2600° C., 2650° C., or 2700° C., or a range between anytwo of the foregoing values. A “substantial absence of structuralshrinkage” and a “substantial preservation of BET surface area” as usedherein generally means that either of these parameters change by no morethan about 5%, and more preferably, no more than about 1%, 0.5%, or 0.1%after heat treatment as compared to the original value before heattreatment. A “substantial preservation of mesoporosity” as used hereingenerally means that the pore volume due to micropores or macroporesdoes not increase by more than about 5%, and more preferably, no morethan about 1%, 0.5%, or 0.1%, as compared to the total pore volume.

Without being bound by any theory, it is believed that the highly acidiccondition employed in the present invention is primarily responsible forimparting the observed enhanced physical properties. In particular, itis believed that the highly acidic condition promotes a self-assemblymechanism by a Coulombic (i.e., ionic) interaction between phenol groupsand templating groups, as opposed to a hydrogen-bonding interactionwhich dominates the self-assembly mechanism under weaker acidicconditions. Since ionic interactions are known to be generally strongerthan hydrogen bonding interactions, the ionic interaction is believed tomore firmly fix the self-assembled precursors in position, and therebyproduce a more rigid and non-labile scaffold before carbonization. Thehighly rigid scaffold produces a stronger and more resilient carbonmaterial after carbonization as compared to carbon materials preparedunder weaker acidic conditions.

Examples have been set forth below for the purpose of illustration andto describe certain specific embodiments of the invention. However, thescope of this invention is not to be in any way limited by the examplesset forth herein.

Example 1 Preparation and Analysis of Mesoporous Carbon Material fromResorcinol-Formaldehyde Polymer (C-ORNL-1)

Mesoporous carbons with highly ordered structure were prepared usingweight ratios of 1.1 resorcinol:1.1 F127:0.48 formaldehyde:3.55-8.2ethanol:5.1-1.67 water:0.16-0.66 HCl. In a typical synthesis, 1.1 g ofresorcinol and 1.1 g of F127 were dissolved in 4.5 ml of ethanol (EtOH),and to this was added 4.5 ml of 3.0M HCl aqueous solution and 1.3 g of37% formaldehyde (37%) was then added. After stirring for 12-13 min. atroom temperature, the clear mixture turned turbid, indicating theformation of the ordered nanocomposite and a phase separation. Afterstirring for a total of 40 minutes, the mixture was centrifuged at 9500rpm for 4 minutes in order to completely separate and isolate thepolymer-rich gel phase. The gel was then loaded on a large Petri dishand cured at 80° C. and subsequently 150° C. for 24 hours each.Carbonization was carried out under nitrogen atmosphere at 400° C. for 2hours at a heating rate of 1° C./min followed by further treatment at850° C. for 3 hours at a heating rate of 5° C./min. The produced carbonmaterial is referred to as C-ORNL-1.

As shown by FIG. 1A, C-ORNL-1 exhibits a type IV nitrogen sorptionisotherm with a sharp capillary condensation step at relative pressurefrom 0.4 to 0.7 and a narrow pore size distribution, centered at 6.3 nm.The calculated BET surface area and pore volume are 607 m²/g and 0.58cm³/g, respectively. As shown in FIG. 1B, C-ORNL-1 displays threewell-resolved XRD peaks which can be indexed into 100, 110, and 200deflections of 2D hexagonal symmetry (p6 mm), indicating a highlyordered mesostructure. The highly ordered 2D hexagonal structure ofC-ORNL-1 is further revealed by the high resolution SEM image (FIG. 2A)and TEM images (FIGS. 2B and 2C, along the [001] and [110] directions,respectively). As shown in FIG. 2, long-range hexagonal arrangement ofporous structure is clearly visible along both the [001] and [110]directions. The cell unit parameter, pore size, and wall thickness ofC-ORNL-1 estimated from the images are 12.2 nm, 6.2 nm, and 6.0 nmrespectively, which are in good agreement with the values determinedfrom the nitrogen adsorption and XRD results. The unit cell parameter ais calculated to be 12.24 nm and the wall thickness to be 5.94 nm.However, the carbon framework wall of CORNL-1 is amorphous, as indicatedby its wide-angle XRD pattern (FIG. 6B).

Example 2 Preparation and Analysis of Mesoporous Carbon Material fromCatechol-Formaldehyde Polymer (C-ORNL-1-c)

The preparation of mesoporous carbons from catechol-formaldehyde andF127 was conducted similarly to the method described in Example 1 above.In a typical synthesis, 1.1 g of catechol and 1.1 g of F127 weredissolved in 4.5 ml of EtOH, and to this was added 4.5 ml of 4.0M HClaqueous solution and 1.3 g of 37% formaldehyde. After stirring for about10 days at room temperature, the clear mixture turned turbid, indicatingthe formation of RF-F127 nanocomposite and a phase separation. Afterstirring for a total of 16 days, the mixture was centrifuged at 9500 rpmfor 4 minutes in order to completely separate and isolate thepolymer-rich gel phase. The gel phase was then cured and carbonized inaccordance with the method of Example 1. The produced carbon material isreferred to as C-ORNL-1-c.

As shown by FIG. 3, C-ORNL-1-c exhibits a type IV nitrogen sorptionisotherm with a sharp capillary condensation step at relative pressurefrom 0.4 to 0.7 and a narrow pore size distribution, centered at 4.9 nm.The calculated BET surface area and pore volume are 418 m²/g and 0.35cm³/g, respectively.

FIG. 4 shows the low-angle XRD pattern of C-ORNL-1-c. A peak at 2θ=0.83is observed, which can be indexed into the 100 reflection of 2Dhexagonal symmetry (p6 mm). In addition, SEM and TEM images (FIGS. 5Aand 5B, respectively) of C-ORNL-1-c clearly show a 2D hexagonalmeso-structure and long range ordering.

Example 3 Thermal Stability Analysis of the Mesoporous Carbon Materials

As further evidenced below, C-ORNL-1 exhibits an unusually high degreeof thermal stability. In particular, FIGS. 6A and 6B show both thelow-angle and wide-angle XRD patterns of C-ORNL-1-x (herein x refers tothe temperature) after heat-treatment at different temperatures, rangingfrom 1800° C. to 2600° C. Surprisingly, C-ORNL-1 still exhibits a strongXRD peak at 2θ around 0.8° after being heated even up to 1800° C. Thelow-angle XRD peak becomes less visible with an increase ofheat-treatment temperature, suggesting a gradual loss of mesostructuralorder. However, the peak position surprisingly does not shift to largerangle, thus indicating an absence of structural shrinkage. Thewide-angle XRD patterns of C-ORNL-1-x clearly indicate the gradualdevelopment of graphitic character of the carbon walls. Surprisingly,the nitrogen sorption isotherms (FIG. 6C) of C-ORNL-1-x show typicaltype IV curves, suggesting that mesoporosity is preserved, even afterbeing heated to 2600° C. However, as shown in Table 2 below, thenitrogen uptake as well as the BET surface area of C-ORNL-1-x tend todecrease with increasing heat-treatment temperature. The pore sizedistribution plots (FIG. 6D) of C-ORNL-1-x show almost identical porediameters for all samples although the mesopores become broader as theheat treatment temperature increases, as also evidenced in Table 1.

TABLE 2 Structural properties of C-ORNL-1-x Surface area Pore volumeMaterials a (nm)¹ Pore size (nm) (m²/g) (cm³/g) C-ORNL-1² 12.24 6.3 6070.58 C-ORNL-1-1800 12.20 6.2 390 0.46 C-ORNL-1-2200 — 6.3 371 0.47C-ORNL-1-2400 — 6.4 288 0.37 C-ORNL-1-2600 — 6.6 230 0.30 ¹unit cellparameter a = 2/√3 * d₁₀₀, pore size is referred to the maximum of thepore size distribution plot based on the BJH method, wall thickness = a− pore size; ²obtained by carbonization at 850° C.

FIGS. 7A and 7B show high-resolution SEM and TEM images, respectively,of C-ORNL-1 after heat treatment at a temperature of 1800° C. (resultingin material referred to as CORNL-1-1800). FIGS. 7C and 7D showhigh-resolution SEM and TEM images, respectively, of C-ORNL-1 afterheat-treatment at a temperature of 2200° C. (resulting in materialreferred to as CORNL-1-2200). FIG. 7E shows a high-resolution SEM imageof C-ORNL-1 after heat-treatment at a temperature of 2400° C. (resultingin material referred to as CORNL-1-2400). FIG. 7F shows ahigh-resolution SEM image of C-ORNL-1 after heat-treatment at atemperature of 2600° C. (resulting in material referred to asCORNL-1-2600). The apparent hexagonal arrangement of mesopores is stillobserved for CORNL-1-1800, suggesting an ordered mesostructure ismaintained, which is in good agreement with the results of XRD andnitrogen sorption analysis. The mesoporous carbon materials being heatedat higher temperatures (i.e., 2200-2600° C.) exhibit wormy structures(FIGS. 7C-F). Surprisingly, all of the above data indicate that CORNL-1can be graphitized at 2400° C. or 2600° C. to form a highly graphiticmesoporous carbon while maintaining substantial mesoporosity and BETsurface area. The high thermal stability of C-ORNL-1 is believed to beat least partially due to the highly crosslinked resorcinol-formaldehydepolymer and resulting highly rigid carbon framework afforded by thehighly acidic conditions used in the present invention. The thick carbonwall is also believed to contribute to the high thermal stability.

While there have been shown and described what are at present consideredthe preferred embodiments of the invention, those skilled in the art maymake various changes and modifications which remain within the scope ofthe invention defined by the appended claims.

1. A method for fabricating a mesoporous carbon material, the methodcomprising subjecting a precursor composition to a curing step followedby a carbonization step, the precursor composition comprising: (i) atemplating component comprised of a block copolymer, (ii) a phenoliccompound or material, (iii) a crosslinkable aldehyde component, and (iv)at least 0.5 M concentration of a strong acid having a pKa of or lessthan −2, wherein said carbonization step comprises heating the precursorcomposition at a carbonizing temperature for sufficient time to convertthe precursor composition to a mesoporous carbon material.
 2. The methodof claim 1 wherein said block copolymer comprises a poloxamer triblockcopolymer.
 3. The method of claim 1, wherein said mesoporous carbonmaterial is in the form of a film having a thickness of less than 1micron.
 4. The method of claim 1, wherein said mesoporous carbonmaterial is in the form of a film having a thickness of or less than 100nm.
 5. The method of claim 1, wherein said curing step comprises heatingthe precursor composition at a temperature of at least 80° C. for atleast 24 hours.
 6. The method of claim 1, wherein said carbonizationstep comprises heating at a temperature of at least 400° C. for at least2 hours.
 7. The method of claim 1, wherein said strong acid is selectedfrom the group consisting of hydrochloric acid, hydrobromic acid,hydroiodic acid, sulfuric acid, and triflic acid.
 8. The method of claim1, wherein said strong acid is in an effective concentration of at least1.0 M with respect to the total volume of precursor composition.
 9. Themethod of claim 1, further comprising mixing the components of theprecursor composition, prior to curing and carbonization, until agel-like phase and a liquid phase begin to separate.
 10. The method ofclaim 9, further comprising isolating the gel-like phase from the liquidphase, and subjecting the gel-like phase to the subsequent curing andcarbonization steps.
 11. The method of claim 1, wherein saidcrosslinkable aldehyde component comprises formaldehyde.